var szPlaybackURI =
  'rtsp://172.9.4.222/Streaming/tracks/101/?starttime=20131223T030658Z&endtime=20131223T031657Z&name=02000000076000101&size=115665012';
var fileName =
  'T_' + szPlaybackURI.substring(szPlaybackURI.indexOf('name=') + 5, szPlaybackURI.indexOf('&size=')) + '.mp4';
console.log(szPlaybackURI.length);
var size = szPlaybackURI.substring(szPlaybackURI.indexOf('size=') + 5, szPlaybackURI.length);
console.log(size);
